Treatment of respiratory diseases by inhalation of fine rock salt particles (halotherapy) in salt caves or salt mines has been practiced for centuries in places such as Eastern Europe. The efficacy is associated with the unique micro climate within the salt caves and mines. The main curative factor is an atmosphere saturated with dry sodium chloride aerosol with particles of 2 to 5 microns in size. The salt aerosol is formed by the convective diffusion of the fine salt particles from the salt walls. Halotherapy has been recognized as a highly effective drug-free treatment for patients with various forms of chronic nonspecific pulmonary diseases. In a typically treatment, a patient will reside in the salt caves for up to twelve hours per day, breathing in the fine salt powder. In areas where salt mines are not available, special rooms have been constructed in which the environmental conditions of the salt mines are artificially reproduced. The patient resides in the halotherapy rooms in like manner as for the salt caves or mines.
Recent studies have indicated that much shorter exposures to aerosolized dry powder salt can provides relief of symptoms of common colds, e.g., sore throat, cough, headache, etc. These studies were conducted with a bench top laboratory system having a means for aerosolizing a quantity of fine powdered salt located within an enclosed chamber. One wall of the chamber included an opening at which a patient's face was positioned so that the atmosphere of aerosolized dry powder salt was available for inhalation. The bench top system provided the respiratory benefit without requiring the patient to be physically located within the chamber. While the patient was not inconvenienced by having to remain in a cave for an extended period, the patient was effectively restricted by the laboratory system. A portable powder delivery system is therefore needed for commercial usefulness of halotherapy.
Aerosolized liquid saline sprays, that are delivered by rather complex medical hardware, are often used in intensive care facilities. These sprays are commonly used to increase mucociliary clearance. However, liquid saline sprays are not well suited in size and cost to provide relief of symptoms to the common cold sufferer because the salt in a liquid saline solution is highly diluted. Thus, liquid saline sprays do not deliver the much higher concentrations of salt to the airways of the lower respiratory tract possible with dry salt powder inhalation.
It has also been long recognized that gargling with a salt solution provides relief from some of the symptoms of colds, primarily sore throat. In fact some studies have indicated that the relief afforded by a salt gargle matches the performance of some over-the-counter sore throat sprays and lozenges. However beneficial salt water gargling may be, it is usually inconvenient to avail oneself of such a remedy.
There are available dry powder inhalers (DPI) which are intended to deliver drugs to the lower portion of the lower respiratory tract, primarily to the lungs, for relief of ailments of the lungs, such as asthma, or to provide systemic drug delivery through the very large surface and thin membranes of the lungs. Accordingly, the drug particle size and properties are optimized for delivery to the lower portion of the lower respiratory tract. For example, particle sizes in the range of 1 microns to 5 microns are useful for powder delivery to the lungs.
Halotherapy for treatment of cold symptoms is directed to the topical application of salt particles at the upper portion of the lower respiratory tract. A portable dry powder delivery system, matched to the desired distribution of the salt particles, is needed for a convenient means for providing drug free cold symptom relief. Furthermore, convenient topical application of salt powder to the upper portion of the lower respiratory tract can provide relief from everyday discomfort due to such problems as allergies, post nasal drip, etc. Moreover, other ingredients may be added to a salt powder, such as menthol or breath fresheners, that could provide an aid in routine throat clearing and freshening of breath.
It is therefore an object of the present invention to provide a method which can deliver dose quantities of dry fine powdered sodium chloride for topical treatment of the upper portion of the lower respiratory tract from a simple and inexpensive portable delivery device.